1. Field of the Invention
The present invention relates to a method of molding a resin casing that partially covers at least a stator of a motor, and a motor.
2. Description of the Related Art
A molded motor has been known in the past. The molded motor includes a housing in which a stator is embedded and which is made of a resin. A rotor is disposed in the housing. The molded motor is excellent in terms of the waterproof property of the stator and vibration resistance and a sound insulating property when the motor is driven.
For example, Japanese Unexamined Patent Application Publication No. 2001-268862 discloses a molded motor in the related art. Japanese Unexamined Patent Application Publication No. 2001-268862 discloses a method that holds a core by stepped portions formed at the center core of a mold and performs molding (Paragraph No. [0004] and FIG. 3).
In FIG. 3 of Japanese Unexamined Patent Application Publication No. 2001-268862, inner end faces of teeth protrude inward from an insulator. Further, the portions, which protrude inward from the insulator, of the teeth are placed on stepped surfaces of the center core of the mold. Further, to facilitate the insertion of the stator into the mold, a small gap is formed between an outer peripheral surface, which is present below the stepped portions of the center core of the mold, and the insulator.
However, the thickness of a resin formed between the center core of the mold and the insulator is small in this structure. In particular, if the insulator is inclined toward the center core of the mold due to the pressure of the resin that is in a flowing state when molding is performed, the resin between the center core of the mold and the insulator becomes thinner. The thinner resin is likely to peel from the insulator. Further, if the resin peels from the insulator, the peeled resin comes into contact with the rotor and noise or failure may be caused.
At least an embodiment of the invention provides a molding method and the structure of a motor that can suppress inward inclination of wall portions of an insulator in a radial direction during the molding of a resin casing.